The way microcapsules are bound to fibres is usually with binders that cover the whole area of the fibres and the microcapsules.
Usually microcapsules of controlled release are applied with binders on the surface of fabrics or knitwear so that they rupture by friction thereby releasing the active product, be it a fragrance, antimicrobial, insect repellent, antioxidant or vitamins.
Thermochromic pigments are also applied in this way. PCM need a thicker material so that they can act efficiently as an insulation or temperature regulating material. The application of PCM microcapsules to fibres with binders is described in the U.S. Pat. No. 5,366,801. Patent WO 0 212 607 describes an application to webs of fibres where the microcapsules of PCM are totally inside the binder and the binder forms a film at the intersection of the fibres.
U.S. Pat. No. 4,774,133 describes the incorporation of microcapsules in textile articles with a thermoplastic film that is applied with heat and pressure.
This application of binder means that a film is formed between the fibres, which makes permeability to air and vapour, and therefore body transpiration difficult.